Measuring dust deposition and generation rates is important for both its fundamental physics and the application of indoor air quality control. These measurements are very difficult to conduct directly in occupied livestock buildings. Two indirect methods were developed for the measurement of both deposition and generation rates under steady-state conditions and unsteady-state conditions respectively. A new mathematical model of particle size distribution was also developed for swine building dust. Based on the mass balance equation for a typical well mixed ventilation space, the nonlinear mathematical solutions were derived. For steady-state conditions, a transformation was employed to the nonlinear solution so the linear model was obtained. Then the sequential parameter estimation method was developed to estimate both dust deposition and generation rates. The input data were airborne dust concentrations versus filtration efficiency. This steady-state method actually converted the difficult measurements of dust deposition and generation rates into the simple measurements of dust concentrations versus filtration efficiency. For unsteady-state conditions, the nonlinear parameter estimation technique was employed to estimate the unknown parameters in the solution of the model. The input variable to this model was dust concentration versus time. The estimated unknowns were dust deposition and generation rates. This unsteady-state method actually converted the difficult measurements of dust deposition and generation rates into the simple measurements of dust concentration versus time. For the validation of the steady-state method, two sets (six sub-sets) of steady-state condition experiments were conducted in the laboratory and the data were compared to computer simulations. Three experiments were conducted to validate the unsteady-state method. The proposed methods were also tested using data from Gao and Feddes (1992) for steady-state conditions, and from Wadden and Scheff (1983) for unsteady-state conditions, respectively.

It is often desired to represent the size distribution of particle populations with a continuous function. Three functions commonly used for this purpose, the normal, log-normal, and Rosin-Rammler distributions, have drawbacks in this regard related to infinite range, shape, and for the last two mentioned, dependent mode and variance. Two functions which avoid these problems have been proposed elsewhere, the modified beta and modified normal distributions. It was shown in this work that these distributions are virtually interchangeable, so the modified beta distribution is favored for use due to its having greater explicitness and fewer constants. The modified beta distribution was then successfully fit via both non-linear regression and direct calculation to reasonably narrow versions of the normal, log-normal, and Rosin-Rammler distributions. Aggregation or disintegration of a particle population often results in multi-modal size distributions. The first of these processes may be viewed as taking place via two mechanisms, either unit or cluster growth, with the second occurring via either erosion or shattering. A bimodal form of the modified beta distribution was used in combination with simple assumptions to describe aggregation and disintegration processes via each of these mechanisms. The same distribution was used to successfully fit size data from disintegrating instant coffee. An erosion index for bimodal size distributions was introduced, and seen to be useful in characterizing disintegration processes. Correlation of the erosion and shattering mechanisms of breakage with the first-order kinetic model of disintegration was attempted. A modification of this model, incorporating the bimodal modified beta distribution to define the breakage function, was used successfully to simulate disintegration processes occurring via either erosion or shattering. Empirical segregation distributions for binary powder mixtures were introduced along with a related index of segregation. These distributions were seen to be useful for comparing the new segregation index with Williams' index of segregation. The new index was found to be generally more sensitive to the progress of segregation than Williams' index, having the further advantage of being unaffected by compaction. Density variation had little effect on both indices.

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A process was developed for converting small sized, underutilized fish particles into fillet analogues. Comparisons were made between the physical properties of natural and analogue fish fillets (e.g. shear stress, compression stress, cooking loss, oil uptake, etc.). An image analysis was carried out to compare muscle fiber sizes and distributions of natural fish fillets and fish fillet analogues. A plasticating extruder was used to restructure the small sized fish particles into continuous extrudates which were then used to fabricate fish fillet analogues. The extrudates contained 60% w.b. moisture and various levels of CMC and Xanthan. A cooled die extension was designed and built for use with the extruder to prevent puffing and moisture loss when extrudates emerged from the die opening. The output product obtained was an extrudate that retained its structure when rehydrated to 80% w.b. in warm water and whose textural properties had distinct similarities to those of natural fish muscle. Statistical comparisons showed that there were no differences (P $<$ 0.01) between corresponding physical properties of fish fillet analogues and natural fish fillets. Structural analyses of natural fish fillets and fish fillet analogues revealed less binding between the fibers in fish fillet analogues than in natural fish fillets. Image analyses showed that the diameters of muscle fibers of fish fillet analogues was quite similar to those of natural fish fillets. The texture of the fish fillet analogues produced was much like Atlantic cod fish fingers after cooking. Tests showed that the product was easily severed with the edge of a fork. When the analogues were chewed, they were much like intact cod fish muscle.

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